Parquet flooring block and method of making same

ABSTRACT

A PREFINISHED UNIT OF PARQUET BOORING IMPREGNATED THROUGHOUT THE TOTAL THICKNESS THEREOF WITH A MONOMER THAT IS POLYMERIZED TO A PLASTIC MATERIAL HAVING A HIGH RESISTANCE TO ABRASIVE WEAR. THE SEPARATE SLATS, WHICH MAY BE QUITE THIN, ARE ASSEMBLED IN BLOCKS PRIOR TO CONVERSION FROM ORDINARY WOOD TO A WOOD-PLASTIC COMPOSITE, AND THE BLOCK MAY THEREAFTER BE PREFINISH BEFORE SHIPPING AND EASILY LAID ON A SUB-FLOOR WITHOUT THE NEED FOR ONSITE FLOOR FINISHING CREWS.

y 18, 1971 1.. G. BARRETT 3,579,410

PARQUET FLOORING BLOCK AND METHOD OF MAKING SAME 2 Sheets-Sheet 1 FiledSept. 6 1967 FIG. 3

INVENTOR LAWRENCE G. BARRETT M, M, MM, Arman M46;

ATTORNEYS y 1971 L. G. BARRETT PARQUET FLOORING BLOCK AND METHOD OFMAKING SAME 2 Sheets-Sheet 2 Filed Sept. 6, 1967 FIG? INVENTOR BARRETTBY dwkzr a WL-r4,-

ATTORNEYS United States Patent Q 3,579,410 PARQUET FLOORING BLOCK ANDMETHOD OF MAKING SAME Lawrence G. Barrett, Lynchburg, Va., assignor toThe American Novawood Corporation, Lynchburg, Va. Filed Sept. 6, 1967,Ser. No. 665,860 Int. Cl. E04f 13/10, 13/18, 15/16 U.S. Cl. 161-38 6Claims ABSTRACT OF THE DISCLOSURE The present invention relates to aunique flooring block which is made from a wood-plastic composite andeither finished after installation or prefinished at the factory.

Parquet flooring units have long been used in the flooring industry.Heretofore, it has been the practice of the industry to produce and tosupply unfinished flooring units bonded by a backing, such as paper, onone or both sides. These unfinished units are conventionally laid on asubfloor in a mastic compound, leveled, and finished in a manner typicalof other types of wood flooring after removal of any upper surfacecovering. Certain deficiencies in the laying of unfinished flooring arereadily apparent upon consideration of the cost and often the difficultyin obtaining the services of skilled labor in performing the finishingof the fioor in situ, floors conventionally requiring extensive sandingand multiple coats of a protective varnish or the like. Paint and otherfinishing materials, sand paper, sanding machines, etc., must betransported to the site and there maintained in sufiicient supply and inoperating condition in anticipation of the progress actually made inlaying of the floor. The unfinished flooring units, in addition, aresubjected to a number of hazards including substantial dimensionalchanges when exposed to changes in moisture during storage and handling.

To eliminate a number of the foregoing disadvantages, the production ofprefinished flooring panels has been adopted. The desired finish isplaced on these flooring units under the controlled conditions of themanufacturing plant and such flooring units have a more uniform and ahigher quality appearance. These prefinished units, while lessresponsive to dimensional changes due to moisture during shipping andstorage because of the finish on their upper surface, are stillsubjected to some dimensional instability due to the absorption ofmoisture through the unprotected ends and the underside of the unit.

By the use of a wood-plastic composite, many of the foregoingdisadvantages are eliminated. The wood-plastic composite used inaccordance with the present invention is basically wood that has beenimpregnated with a monomer that is subsequently polymerized therebyproviding several improved properties to the wood. The surfaces3,579,410 Patented May 18, 1971 are relatively impervious to moisturewhich reduces undesired dimensional changes and produces improved stainresistance which is important where foods, pet excretion and the likeare in evidence. Any staining which occurs from strong solvents isreadily removed by use of household cleansers or steel wool.

Among the other important advantages is the fact that the polymers usedmay have greatly increased resistance to wear and abrasion. Even if thesurface wears down, as would occur in regions of heavy traffic, thefinish may be made uniform throughout the thickness of the flooring unitand the desirable surface appearance properties are retained without theneed for frequent refinishing.

Because of the added cost necessary to convert wood into a wood-plasticcomposite, it is important to minimize the dimensional thickness of theflooring block to be competitive with conventional flooring. Use ofthicknesses down to about 4; inch introduced certain problems ofprocessing and handling of the flooring.

It is therefore the main object of this invention to provide a novelwood-plastic composite flooring block or unit which has superiorwear-resistant properties and which may require no paint or lacquers inthe finishing thereof, but which can be finished by the sole step ofpolishing the exposed surface.

Another object is to provide a novel parquet flooring block or unit madefrom slats of a wood-plastic composite which may be in situ leveled toprovide an improved appearance of the completed floor.

Yet another Object of the present invention is to provide a parquetflooring unit made from slats of a woodplastic composite where the slatsare held together during the conversion of the wood by unuiquetechniques, such as by use of splines, backing members and/or frameswhich may or may not be removed after the wood is converted.

A further object is to provide a novel process for making thewood-plastic composite flooring block wherein the slats are assembledtogether before conversion and the polymer upon conversion aids inholding the individual slats together as a flooring block. Where abacking mem her is used, it may, if porous, be quite flimsy and weakbecause after impregnation and conversion, the polymer greatly adds toits strength and to the adhesive force holding the backing member to theflooring block. The backing member may, if desired, be allowed to extendbeyond the periphery of the flooring unit to thus aid in holdingtogether adjacent flooring blocks when placed on a sub-floor in asuitable adhesive or mastic.

These and other objects and advantages of the present invention willbecome more fully apparent from the appended claims, and from thefollowing description when read in conjunction with the drawings,wherein:

FIG. 1 is a perspective view of the novel parquet flooring unit of thepresent invention;

FIG. 2 is an enlarged fragmentary bottom view of one corner of theflooring unit of FIG. 1 illustrating the use of a loosely woven backingmember;

FIG. 3 is an end view illustrating the ability of the flooring units ofFIG. 1 to conform to irregularities in the sub-floor;

FIG. 4 is a bottom view of a flooring unit having a porous fiber backingfor holding the slats together in a flooring block;

FIG. 5 is a pictorial view of a flooring unit wherein the slats are heldtogether by a spline;

FIG. 6 is a view of a flooring unit wherein the slats are held togetherduring the conversion process by a frame that is adapted to be removedafter the conversion process is completed; and

FIG. 7 is a view partially in section showing a multiple ply flooringblock having one or more veneer layers of wood-plastic composite.

Referring now to the drawings, the novel parquet flooring unit 10 of thepresent invention comprises a plurality of squares 12 each made up of anequal number of elongated slats 14 assembled in a side-by-siderelationship. The slats 14 are substantially uniform in size.Conventionally, such squares have side edges that range from betweenapproximately /2 to 2 /2 inches, and the thicknesses usually exceed /2inch. However, the present invention is characterized in part by thefact that the thickness may be as little as inch, and a /8 inchthickness is regarded to be a maximum that would ever be needed. Thesquares 12 may be conveniently arranged so that the grain of all of theslats 14 of each square 12 extends longitudinally in the same directionand the adjacent squares 12 oriented at 90 to each other to present analternating or checkerboard configuration. Obviously, other shapes andgrain patterns may be adopted, as the particular orientation of thegrain pattern is no part of the present invention.

As shown in FIG. 2, the individual slats 14 are assembled on a looselywoven backing member 16 which may conveniently be thread, or a strand ofa suitable material such as cotton, or a first thermoplastic resin thatis applied to the slats 14 with another or the same thermoplastic resin.It will be appreciated that the backing member as illustrated in FIG. 2comprises strands formed in a Woven pattern with the spacing betweenstrands being much larger than the thickness of the strands. The choiceof material for the backing member 16 is dictated in part by the woodconversion process as will be hereinafter explained and must afterconversion possess sufiicient strength and be adequately secured to theblock to hold the slats 14 together during their further handling. Ifthe blocks are prefinished at the factory, then the backing member mustmaintain the slats together while the flooring block is processedthrough a subsequent sanding and pumicing operation.

A chamfer 18 may be cut along the upper periphery of the flooring unit10 to reduce slight variations in the height of adjacent flooring units10 due to irregularities in the sub-flooring 20. Some of the need forleveling may be eliminated in this manner.

Flooring units 10 of the character described may be readily andconventionally installed in the manner of asphalt or plastic tiles byapplying a suitable mastic or the like on the sub-floor 20 to apredetermined thickness and laying the flooring units 10 in the masticin an abutting edge-to-edge relationship. Due to the looseness of theweave of the backing member 16, a large portion of the underside 22 ofthe flooring units 10 are exposed and a bond may be achieved directlybetween the sub-flooring 20 and the individual slats 14 which comprisethe flooring unit 10.

As shown in FIG. 3, the flooring units 10 laid on an uneven sub-floor 20will accommodate themselves to the contours of the sub-floor by reasonof the lack of any connection between slats 14 other than the flexiblebacking member 16. The short length and orientation of the individualslats also contribute to the ability of the flooring unit 10 to conformto the contours of the sub-floor 20.

The vastly improved abrasive wear characteristics of the flooring units10 of the present invention are achieved through the conversion of thewood to a wood-plastic composite. The conversion process is disclosedand claimed in my copending US. application, Ser. No. 678,584, filedOct. 27, 1967, for Method and Apparatus 4 for Converting Wood to aWood-Plastic Composite, which is hereby incorporated by reference.

In the process there disclosed, the individual slats 14 are cut to sizefrom a suitable wood having the grain characteristics desired to bedisplayed in the finished floor. The slats 14 are then assembled on thebacking member 16 in the desired configuration and held in place by asuitable adhesive.

The choice of a material for the backing member 16 is dependent on anumber of factors including the choice of the monomer with which theslats 14 are to be impregnated in the conversion process. The choice ofthe monomer is of course determined by the characteristics desired inthe converted article. A monomer that has certain desirable propertiesis methylmethacrylate; polymerization may be effected by exposure togamma radiation. If the slats are to be impregnated with the monomer andthen converted by the polymerization thereof within the wood afterassembly on the backing member, the backing member 16 is advantageouslyrelatively insoluble in the monomer.

Conversion of the wooden slats to a wood-plastic composite results invastly improved abrasive wear characteristics which extend to the depthof the monomer penetration. Where the penetration extends through thetotal thickness of the slats, the wear-resistant and desirableappearance properties extend completely through the thickness of theslat. Thus, as the surface wears down, the new surface that is exposedhas the same properties as the original upper slat surface, andrefinishing as is customarily required on wooden flooring is notrequired. Moreover, the rate of wear is reduced so that the actualthickness of the slats can be as little as Ms inch for manyapplications, and even in the heaviest traffic areas, a thicknessexceeding /8 inch is not required.

One important aspect of the present invention resides in the assemblingof the wooden slats prior to conversion of the wood into a wood-plasticcomposite. Several advantages in the finished fiooring unit or blockresult from having secured together a number of slats into an integralunit prior to the point in time when the slats are loaded with themonomer which is, of course, prior to the conversion step. Severaltechniques may be employed, and that shown in FIG. 1 involves the use ofa backing member 16, which has been described above.

An important consideration in the conversion process with the slatsalready assembled in blocks is the swelling of the wood. By way ofexample, red oak having a 5% equilibrium moisture content will swellvery little along the grain but each quarter sawn slat 14 of theflooring unit 10 having overall dimensions of 11 x 11 inches willincrease approximately .008 in width. It is thus necessary to compensateby reducing the dimensions of the slats 14 an appropriate amount priorto conversion. This may be accomplished by cutting the strips 14undersize or by controlled drying to shrink the slats to a size whichwill swell to the dimension desired upon impregnation.

After conversion of the flooring unit 10, i.e., the backing member 16and assembled slats 14, the flooring unit 10 may be finished simply bysanding and polishing the upper surface thereof. This may beconveniently accomplished in the manner suitable for sandingconventional prefinished parquet flooring through the use of multipledrum or belt sanders (not shown) having successive stages utilizingsandpaper having a progressively finer grit. The final polishing of theupper surface of the flooring units may also be accomplished in aconventional manner through the use of pumice or other fine gritabrasive substance.

The wood of the flooring unit 10 that is converted to a wood-plasticcomposite has a finish that is coextensive with the depth of conversion.It will be appreciated, however, that the wood is advantageouslyimpregnated with the monomer throughout the total thickness of the slats14. Normal abrasive wear will reduce the thickness of the flooring units10, but will not appreciably detract from the quality and lustre of thesurface thereof. The black stains commonly found in parquet flooring,stains resulting from food or pet excrement, are easily removed.Significant marring may be eliminated by spot sanding or buffing theappropriate portion of the upper surface of the flooring units 10 with amild abrasive such as pumice or the like. The upper surface may receiveadditional protection in the form of a conventionally applied coating ofcommercially available flooring wax.

Should unevenness of the sub-flooring result in a discontinuity betweenthe upper surfaces of adjacent flooring units 10 to an extent that thechamfer 18 of the upper periphery thereof does not obviate the necessityfor in situ leveling, the high spots may be easily spot sanded toaccomplish leveling of the floor without fear of inability to match theappearance of other portions of the floor.

By the foregoing, it can be seen that the prefinished flooring units 10may be quickly and easily installed to form a complete floor which isimmediately ready for use after the leveling thereof. The elimination ofthe necessity for finishing the surface of the floor in situ or ofattempting to match the factory applied finish of adjacent flooringunits after spot leveling is a material advance in the art. In addition,the bonding of the individual slats 14 directly to the sub-floor 20enhances the permanence of the floor.

Referring now to FIG. 4, a block of flooring 26 is il lustrated whereinthe slats 28 are secured together by two strips 30 and 32 of a fibrousmaterial that is porous to be absorptive of the monomer. Strips 30 and32 may be initially applied to the bottom surfaces of slats 28 by anysuitable adhesive. The entire block is then impregnated with the monomerwhich is also absorbed by strips 30 and 32. Upon conversion, thepolymerization of the monomer increases the bonding strength of strips30 and 32 to slats 28. Thus, it is not necessary that the backingmembers in the form of strips 30 and 32 completely cover the lowersurface of slats 28 as in the case of the embodiment shown in FIG. 2,though in some applications this may be desirable.

Strips 30 and 32 may be a paperboard or felt and have relatively lowstrength before the conversion process, since after polymerization ofthe absorbed monomer, their rigidity and strength are substantiallyenhanced. Since the thickness of strips 30 and 32 is small, it isadvantageous to have the marginal edges extend beyond the periphery ofblock 26 so that during installation of the floor, they will extendunder adjacent blocks and thus reduce the tendency of the blocks toseparate.

FIG. illustrates yet another technique by which the slats of a block maybe held together. In FIG. 5, the slats 34 of the block are provided witha slot 36 along the ends. A spline or dowel 38 is provided in slot 36.By providing a similar construction at the opposite end, slats 34 may beheld in a unitary block during the conversion process and thereafterhandled without separatmg.

Referring now to FIG. 6, an arrangement is illustrated wherein slats 40,which form the flooring unit or block, are held together prior toloading with the monomer by a suitable frame or clamp which is removedbefore the flooring unit is placed into use. The clamp may be in theform of flexible metal strips which engage the outside edges of theslats 40, as illustrated in FIG. 6, and which extend above the Wearingsurface of the flooring unit to thereby minimize interference whenloading the slats with the monomer. If sufiicient monomer does notpenetrate along joints 44 between adjacent slats to bond the slatstogether, a slight spacing may be provided between portions of theabutting slat edges to accommodate a thin layer of monomer which, whenpolymerized, serves to hold the slats together even after removal of theclamps 42. Clamps 42 may be removed at the factory before shipping andreused during the conversion process.

In some instances, it may be desirable to use a backing member which isvery limber and incapable of holding the slats together in asatisfactory manner prior to conversion into the wood-plastic composite.The use of a frame or clamping arrangement, such as illustrated in FIG.6, together with such a backing member which will absorb monomer andgain sufiicient rigidity during the polymerization process to serve asan efiective backing member, may be advantageous.

Referring now to FIG. 7, a flooring unit is illustrated which islaminated in construction. The upper layer 46 may be a face veneerhaving a thickness on the order of inch. The upper layer 46 ispreferably impregnated throughout the total thickness thereof with amonomer that is later polymerized to a plastic material to provide highresistance to wear due to abrasion. The re maining layers may also betotally impregnated. Small grooves 48 may be provided to produce smallsections which simulate a slat construction used in parquet flooring.The lower layer 50 serves as a backing member, and one or morecross-bands having their grain disposed at not less than 45 from thedirection of the grain of the adjacent sheets may be provided as layer52. All of the layers are joined together with a suitable adhesive. Thetotal thickness of the laminated flooring unit is preferably between /sand inch, and each of the sheets of wood preferably is less than 1/ 16inch thick.

The invention may be embodied in other specific forms without departingfrom the spirit of the invention or essential characteristics thereof.The present embodiments are therefore to be considered in all respectsas illustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. A method of providing parquet flooring of a woodplastic compositecomprising the steps of:

(a) providing wood in the form of substantially uniformly dimensionedslats having initial dimensions less than a final size between about 3inches and 12 inches in length, between about /2 inch and 2 /2 inches inwidth, and between about A; inch and inch in thickness;

(b) assembling the slats together to form a flooring unit having upperand lower surfaces and maintaining the assembled slats in an assembledunit with a backing member secured to a lower portion of each slat inthe unit, the backing member comprising spaced strands, each of saidstrands extending across the intersection of at least two adjacent slatswith the spacing between the strands being much larger than thethickness of the strands thereby to expose a substantial portion of thelower surface of the flooring unit for bonding directly to a subfloor;

(c) impregnating the assembled slats throughout the total thicknessthereof with a liquid monomer to swell the slats to dimensions not lessthan and sub stantially equal to the dimensions of said final size;

(d) converting the impregnated slats to a wood-plastic composite bypolymerizing the impregnated monomer; and

(e) bonding the exposed lower portion of a flooring unit directly to asubfloor.

2. The method according to claim 1 wherein the step of providing wood inthe form of substantially uniformly dimensioned slats having initialdimensions less than the dimensions of the final size includes cuttingthe strips to the initial dimensions.

3. The method according to claim 1 wherein the step of providing wood inthe form of substantially uniformly dimensioned slats having initialdimensions less than the dimensions of the final size includes the stepof drying the slats under controlled conditions to shrink the slats tosaid initial dimensions.

4. The method of claim 1 wherein the spaced strands are provided in aWoven pattern.

5. The flooring assembly produced by the process of claim 1.

6. The flooring assembly produced by the process of claim 4.

References Cited UNITED STATES PATENTS 1,796,880 3/1931 Allen 525862,591,768 4/1952 Austin 117116X 2,835,936 5/1958 Elmendorf 16l--382,887,867 5/1959 Burchenal et a1 161-39X 3,077,417 2/1963 Kenaga204159.12X

'8 4/1964 Tibbals 52586 6/1964 Sisko 1 61-37 10/1966 Dittmar 52390X4/1968 Shook et a1. 16139X 12/1969 Waite 16138X 12/ 1969 Morgan et a1117-116X FOREIGN PATENTS 1/ 1957 Australia 52384 7/1954 France 52390JOHN T. GOOLKASIAN, Primary Examiner J. C. GIL, Assistant Examiner US.Cl. X.-R.

